/*
 * Package il.ac.biu.cs.grossmm.impl.server
 * File MappedLoader.java
 * 
 * This is a part of presence service framework prototype. 
 * See javadoc for more information.
 *  
 * Copyright (C) 2006 Grossmann Mark
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Lesser General Public License for more details.

 * You should have received a copy of the GNU Lesser General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 */

package il.ac.biu.cs.grossmm.impl.server;

import java.util.Map;

import il.ac.biu.cs.grossmm.api.server.Loader;
import il.ac.biu.cs.grossmm.api.server.Wrapped;
import il.ac.biu.cs.grossmm.api.server.Wrapper;
import il.ac.biu.cs.grossmm.api.server.NoSuchComponentException;


public class MappedLoader implements Loader {
	final Loader baseLoader;
	final boolean transparent;
	final Map map;
	
	public MappedLoader(Loader loader, Map map, boolean transparent) {
		this.baseLoader = loader;
		this.transparent = transparent;
		this.map = map;
	}

	public Wrapped load(Wrapper wrapper, Object hint) throws Exception {
		Object baseHint = map.get(hint);
		
		if( baseHint == null )
			if( transparent )
				return baseLoader.load(wrapper, hint);
			else 
				throw new NoSuchComponentException();
		
		return baseLoader.load(wrapper, baseHint);
	}
}
